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1. Field of the Invention
This invention pertains generally to devices for measuring food temperatures, and more particularly to devices for measuring internal temperatures of food patties.
2. Description of the Background Art
When cooking hamburgers and other food patties, it is critical to obtain a certain final temperature to prevent illness. The United States Department of Agriculture (USDA) and the Food and Drug Administration (FDA) have provided guidelines that specify the temperatures values at the center of food patties that must be reached at the end of cooking in order to destroy any pathogenic microorganisms.
Measuring the internal temperature of a food patty such as a hamburger patty, a chicken patty, or a vegetable burger patty, can be difficult. For example, many commercial hamburger patties are approximately ten centimeters (10 cm) in diameter and typically vary in thickness from approximately seven millimeters (7 mm) to approximately twelve millimeters (12 mm). Typically, a hand-held device having a long, thin probe is used to measure the internal temperature of a food patty. In order to properly determine the internal temperature of the food patty, a user must insert the probe into the geometric center of the food patty; namely, at a location within the patty equal to one-half the thickness of the patty from the surface of the patty along its central axis. It is important that the probe is inserted to the geometric center of the food patty because, when the patty is heated from two sides during cooking, the slowest heating point is the geometric center of the food patty. Unfortunately, it can be extremely difficult to accurately insert the measuring tip of a temperature probe to the geometric center of the food patty. This can result in inaccurate and unreliable temperature values, particularly with thinner patties where temperature measurement errors are more pronounced.
For example, research has shown that if the measuring tip of a temperature probe is only one millimeter (1 mm) from the geometric center of the food patty, the temperature difference can be as great as ten degrees Celsius (10xc2x0 C.). The resulting error in the temperature measurement is unacceptable because the FDA requires that hamburger patties must be cooked to a center temperature of sixty eight degrees Celsius (68xc2x0 C.). Currently, many fast-food establishments set the operating conditions of their cooking grills by manually measuring the center temperature of a sample of food patties at the start of every work shift. Due to the above-described errors in manual measurement, operators can unknowingly set grill conditions that can result in either overcooking or undercooking of the food patties. Overcooking simply impairs the quality of the food patties. Undercooking, on the other hand, can jeopardize the health of anyone who consumes an undercooked food patty.
Accordingly, the present invention seeks to overcome the prior art drawbacks, and has provided the below-disclosed solutions to one or more of the prior art deficiencies.
The present invention is an apparatus for measuring internal temperatures of food patties. According to an aspect of the invention, the apparatus includes a temperature probe and a drawer sled for holding a food patty. The drawer sled is movable between a loading/unloading position and a temperature measuring position. In the loading/unloading position, a food patty can be loaded into the drawer sled or unloaded from the drawer sled. Conversely, in the temperature measuring position, the temperature probe is inserted into the food patty. The temperature probe is inserted into the food patty radially (e.g., longitudinally along the patty) to overcome the above-described deficiencies with prior temperature measuring devices were the temperature probe is inserted axially.
In accordance with another aspect of the invention, the apparatus preferably includes a base plate. A first end plate and a second end plate are attached to the base plate. A shaft is installed between the first and second end plates and the drawer sled slides back and forth on the shaft between the first and second end plates. Preferably, a drive screw is engaged with the drawer sled. The drive screw is rotatable to slide the drawer sled along the shaft. Additionally, a motor is mechanically coupled to the drive screw and can be energized to rotate the drive screw.
According to a still further aspect of the invention, the apparatus includes a first limit switch and a second limit switch. The first limit switch can be toggled to de-energize the motor when the drawer sled reaches the temperature measuring position. On the other hand, the second limit switch can be toggled to de-energize the motor when the drawer sled reaches the loading/unloading position.
Preferably, a drawer cavity is established within the drawer sled. The drawer cavity is cylindrically shaped to receive a generally cylindrically shaped food patty. Further, a spacer, made from a material having a low thermal conductivity, can be disposed within the drawer cavity. In a preferred embodiment, the apparatus includes a temperature probe brush that is installed in the drawer sled. As the drawer sled moves back and forth along the shaft, the temperature probe slides through the temperature probe brush. Also, a temperature meter is connected to the temperature probe.
Another aspect of the invention is a method for measuring internal temperatures of food patties comprising inserting a central temperature probe radially into a food patty until the temperature probe reaches a geometric center of the food patty. Once the temperature probe is inserted in the food patty, an internal temperature of the food patty is measured at the geometric center of the food patty.
According to still another aspect of the invention, the apparatus includes means for measuring temperature and means for supporting a food patty. The means for supporting the food patty is movable between a loading/unloading position and a temperature measuring position. In the loading/unloading position, a food patty can be loaded into the means for supporting or unloaded from the means for supporting. Conversely, in the temperature measuring position, the means for measuring temperature is inserted into the food patty.
Further aspects of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon.